通過rpy2將Python Lambda函數傳遞給R

Question

我想圍繞R庫Rdtq（ https://github.com/cran/Rdtq ）編寫一個Python包裝器。 該庫（或更確切地說，類實例）將兩個函數作為主要輸入：漂移f（x）和擴散g（x）。 例如，

my_drift = function(x) { -x }
my_diff  = function(x) { rep(1,length(x)) }

由於我正在圍繞Rdtq類編寫包裝器，因此我想直接從Python傳遞漂移和擴散函數，最好是通過lambda函數傳遞

my_python_drift(x) = lambda x: -x
my_python_diff(x)  = lambda x: np.ones(len(x))

等等。 因此，更籠統地說，我的問題是：是否可以通過rpy2將Python lambda（或全局）函數作為參數傳遞給R？

Answer 1

考慮使用rpy2的SignatureTranslatedAnonymousPackage（STAP）導入任意R代碼作為Python環境中的可用包。 為了演示，下面使用rpy2將用R編寫的Rdtq github轉換為Python：

[R

# Loading required package: Rdtq
require(Rdtq)

# Assigning drift and diff functions
mydrift = function(x) { -x }
mydiff = function(x) { rep(1,length(x)) }

# Running rdtq()
test = rdtq(h=0.1, k=0.01, bigm=250, init=0, fT=1,
            drift=mydrift, diffusion=mydiff, method="sparse")

# Plotting output
plot(test$xvec, test$pdf, type='l')

蟒蛇

from rpy2 import robjects 
from rpy2.robjects.packages import STAP
from rpy2.robjects.packages import importr

# Loading required package: Rdtq
Rdtq = importr('Rdtq')

fct_string = """
my_drift <- function(x) { -x }
my_diff  <- function(x) { rep(1,length(x)) }
"""

# Creating package with above drift and diff methods
my_fcts = STAP(fct_string, "my_fcts")

# Running rdtq() --notice per Python's model: all methods are period qualified
test = Rdtq.rdtq(h=0.1, k=0.01, bigm=250, init=0, fT=1,
                 drift=my_fcts.my_drift(), diffusion=my_fcts.my_diff(), method="sparse")

# Load plot function
plot = robjects.r.plot

# Plotting by name index
plot(test[test.names.index('xvec')], test[test.names.index('pdf')], type='l')